The present invention relates to valve assemblies and, more particularly, to a valve assembly for use in sampling fluids.
High pressure hydraulic systems experience failures as a result of abrasion and wear of critical component parts either due to the natural abrasion of high pressure high velocity fluid flow acting directly on the components or due to inter-component abrasion where moving parts operate in a high pressure environment. In either case, certain types of failure can be costly or even catastrophic if they are not detected in the incipient stage and no remedial action is taken. One method of detecting incipient failure is to obtain a sample of the hydraulic fluid from the operating system and analyze such sample for the presence of contaminants. For example, a pump in the system may be experiencing wear or erosion and metal from its parts is entering the fluid stream. Detection of such metal in the fluid sample would provide an indication and warning of the potential risk factor.
Apparatus is known for monitoring the fluid in hydraulic systems where the pressure can reach as high as 6000 p.s.i.g. or higher. Such apparatus makes use of a check-valve-controlled tap installed in the hydraulic system to which valve can be connected, by means of a suitable female coupling, a length of small bore flexible hose. The coupling for attaching the hose to the check-valve-controlled tap has a coaxial nipple that penetrates the check valve to unseat the latter upon tightening the female threaded coupling. Generally, a pressure gauge is connected to the free end of the hose and the arrangement is used for briefly observing the pressure at the site of the tap.
If the high pressure check-valve-controlled tap mentioned above is to be used for extracting fluid samples for testing, it is extremely difficult and dangerous to rely upon manipulation of the check valve through the intermediary of the hose coupling for controlling the flow of sampled fluid. It is, therefore, an object of the present invention to provide a valve assembly that can be used safely for extracting a controlled quantity of the hydraulic fluid under conditions that will not introduce additional contamination.